#!/usr/bin/env node

const cp = require('child_process');

console.log(`I am father process.PID:${process.pid}`);
const cat = cp.spawn('cat',['data.txt']),
      sort = cp.spawn('sort'),
      uniq = cp.spawn('uniq');
cat.stdout.pipe(sort.stdin);
sort.stdout.pipe(uniq.stdin);

uniq.stdout.pipe(process.stdout);
uniq.stderr.pipe(process.stderr);

